This paper describes the relationship between the development of skeletal open-bite malocclusion and the tooth-to-denture base discrepancy. The cases which have a severe skeletal open-bite malocclusion are presented to evaluate the causing factor of the anterior open-bite. The anterior open-bite was associated with inferiorly positioned maxillary molars caused by the squeezing out effect of the tooth-to-denture base discrepancy, especially those in posterior part of dentition (posterior discrepancy), which provided a less steep maxillary occlusal plane in the denture frame. It was suggested that the posterior discrepancy induced a descending movement of the posterior teeth followed by a change of the occlusal plane and this effect of the posterior discrepancy was important factor in developing anterior open-bite malocclusion.